Blood Test May Predict Success of Breast Cancer Treatment

Reduction of wait-time and procedures could prove significant

Daniel Hayes Photo: Martin Vloet

Arrows indicate two cancer cells isolated from the blood of a patient with metastatic breast cancer using the CellSearch technology.

Women with advanced breast cancer who have more tumor cells circulating in their bloodstream die sooner than women with fewer of these cells and their cancer progresses more rapidly, according to a new study by researchers from the U-M Comprehensive Cancer Center and 19 other cancer centers throughout the country.

The study found that about half of 177 women whose breast cancer had metastasized, or spread, and who were starting a new treatment, such as chemotherapy or hormone therapy, had elevated levels of circulating tumor cells in their blood system. Investigators defined an elevated level as five or more tumor cells in a blood sample.

Thirty percent of these women still had higher numbers of circulating tumor cells three to five weeks after beginning a new treatment and their cancer progressed very rapidly compared to women whose tumor cell levels dropped during that time, or who never had elevated cell levels. The study used a new technology called CellSearch™ that isolates and characterizes tumor cells. Results of the study were published in the New England Journal of Medicine.

“Identifying the number of circulating tumor cells in patients with metastatic breast cancer, especially at the time of their first follow-up after starting a new therapy, may provide an early, reliable indication of whether that therapy will be successful,” says senior study author Daniel Hayes, M.D., clinical director of the Cancer Center’s Breast Oncology Program and a professor of internal medicine in the U-M Medical School.

Currently, to determine if a therapy for metastatic breast cancer is effective, women must wait up to four months after beginning the treatment and then undergo a series of tests, including bone scans and X-rays. If the technique used in this study proves effective, doctors could determine within several weeks if the therapy is working, with only a routine blood sample from the patient.

Immunicon Corporation funded the study and developed the CellSearch™ system. Hayes has received grants from and served as a consultant for Immunicon.

—NF

Read an expanded version of this story:
www.med.umich.edu/opm/newspage/2004/tumorcell.htm

For patient information on breast cancer:
www.cancer.med.umich.edu/learn/breastinfo.htm